Cathode layer and solid-state battery

Abstract

A cathode layer comprising at least a cathode active material and a solid electrolyte, wherein the cathode active material is cathode active material particles, an average particle diameter of the cathode active material particles is 2.5 μm or more and 4.5 μm or less, and a normalized interface length value A (μm−1) obtained by dividing a length (μm) of an interface between the cathode active material and the solid electrolyte confirmed from a SEM image of a cross section of the cathode layer by an area (μm2) of the cathode active material in SEM image is 1.15 or more.

What is claimed is: 
     
         1 . A cathode layer including at least a cathode active material and a solid electrolyte, wherein
 the cathode active material is cathode active material particles,   an average particle diameter of the cathode active material particles is no less than 2.5 μm and no more than 4.5 μm, and   a normalized interface length value A (μm −1 ) that is obtained by dividing a length (μm) of an interface between the cathode active material and the solid electrolyte that is confirmed from a scanning electron microscope (SEM) image of a cross-section of the cathode layer, by an area (μm 2 ) of the cathode active material in the SEM image, is no less than 1.15.   
     
     
         2 . The cathode layer according to  claim 1 , wherein the average particle diameter of the cathode active material particles is no less than 3.0 μm and no more than 4.0 μm. 
     
     
         3 . The cathode layer according to  claim 1 , wherein the solid electrolyte is a sulfide solid electrolyte. 
     
     
         4 . The cathode layer according to  claim 1 , wherein the cathode active material is a lithium-ion conductive-compound-coated cathode active material in which a lithium-ion conductive compound is coated on at least part of a surface of the cathode active material. 
     
     
         5 . A solid-state battery, including the cathode layer according to  claim 1 .